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Avalanche Forecast

Mar 10th, 2013–Mar 11th, 2013
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: Sea To Sky.

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain on Monday

Weather Forecast

Monday: Overcast conditions with moderate to heavy snowfall developing late in the day / Moderate southwest winds / Freezing level at 1200mTuesday: Moderate to heavy snowfall / Moderate to strong southwest winds / Freezing level at 1300mWednesday: Heavy snowfall / Moderate southwest winds / Freezing level at 1700mNote: The bulk of the precipitation is expected to fall in the south of the region for the forecast period

Avalanche Summary

Before the weekend a size 2.5 slab avalanche was observed above the Squamish River Valley on an east aspect at 2300m. The size of this slide suggests it may have failed on the February 20th interface. On Saturday loose wet avalanches to size 1.5 were reported, one of which triggered a size 2 storm slab in south facing alpine terrain. These occurred in response to solar warming. A few size 1 windslabs have also been reported. These formed from strong southwest winds on Saturday.

Snowpack Summary

Dribs and drabs of recent snowfall have been shifted by strong southwest winds into touchy new windslabs in exposed areas. In more sheltered terrain, surface hoar and/or surface facets are likely to exist. A sun crust has formed on south facing terrain.Between 60 and 110cm below the surface is a layer surface hoar which was buried on February 20th. Although this layer has a history of producing large avalanches, triggering this layer has now become difficult, and would most likely require a very large trigger on a steep, unsupported slope.Below this interface, the snowpack is strong and well settled.

Avalanche Problems

Wind Slabs

Wind slabs exist and are reportedly reactive in some areas. New wind/ storm slabs are also expected to form with forecast weather on Monday afternoon.
Be alert to conditions that change throughout the day.>Be cautious as you transition into wind affected terrain.>

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3